This invention concerns shackles of the type that transport poultry carcasses in sequence along a processing path, particularly through a cut-up line where the poultry carcasses are cut apart. More particularly, the current invention concerns an improved rotary shackle assembly that locks the stirrups of the shackle in predetermined positions after the shackle has been rotated so as to present the bird carried in the stirrups of the shackle to a subsequent processing station.
This invention is directed to an improved, durable rotary shackle for use on a poultry processing line that is of simple construction and that reliably locks the stirrups of the shackle in predetermined positions after the shackle has been rotated to the proper orientation for the next processing station in the processing line.
The typical prior art poultry processing conveyor line includes a suspended conveyor rail and a series of bird support shackles, each of which includes a trolley for rolling along the conveyor rail and a bird hanger, or shackle, suspended below the trolley, with a drive chain connecting the shackles in equally spaced series. The shackles have a pair of spaced depending stirrups that are configured to receive and hold the legs or hocks of the birds.
With this arrangement, the workers at the poultry processing line can suspend the birds by their legs or hocks from stirrups of the shackles by slipping them into the stirrups. The spaced suspension of the legs of the birds and the spaced relationship between the birds along the conveyor system allows the birds to be moved sequentially through the various processing stations, such as the cut-up machines, for serial processing of large numbers of the carcasses.
As poultry carcasses are processed at the various processing stations of the processing line, the carcasses are turned to present the carcasses in various attitudes to the different processing machinery to accommodate each of the processing steps. In some of these stations, it might be desirable to present the carcasses breast first, in other stations back first, and still other stations side first. In order to turn the bird, poultry shackles have been developed that include a turning block that is non-rotatably mounted to the shackle and that is shaped to engage turning pins or cams spaced at predetermined intervals along the poultry processing path. When a portion of the turning block reaches the turning pin, the turning block xe2x80x9cwalks aroundxe2x80x9d the turning pin, so as to rotate the shackle and the bird, usually 90xc2x0.
In order to keep the bird hanger from inadvertently rotating with respect to the poultry processing line, the turning block typically includes flat surfaces about its periphery, and the flat surfaces are arranged to moved adjacent longitudinal guide rails that extend parallel to flat surfaces of a properly oriented turning block so that no inadvertent turning of the shackles or the birds suspended on the shackles will occur. An example of this type of rotary shackle is disclosed in U.S. Pat. No. 5,487,700.
While the above described rotary shackles have met with success in the poultry processing industry, there are times when the poultry conveyor system must be able to move the poultry shackles and the birds carried thereby up and down inclines, around curves and about combinations of curves and inclines. While the prior art turning blocks and guide rails are effective to retain poultry shackles in an approximately fixed attitude along horizontal, rectilinear runs of a conveyor system, the turning blocks and their necessary guide rails are more difficult to construct and operate for movement of the shackles about curves and inclines along the processing path and the guide rails would have been interrupted at the positions along the path where the shackles negotiate a turn, etc. Therefore, this would result in moving poultry shackles at certain intervals along the processing line without using the guide rails to maintain the shackles in a fixed position with respect to the poultry line. This would allow the birds to wander off alignment as they negotiated a curve, etc.
U.S. Pat. No. 5,092,815 illustrates a rotary shackle assembly that has a spring loaded ball bearing that registers with a detent, tending to hold the shackle in a non-rotary position with respect to its trolley. However, the ball and detent arrangement provides only a light restraining force to the tendency of the bird and shackle to rotate with respect to the trolley. The absence of a firm lock does not solve the problem of inadvertent rotation of the poultry carcass with respect to its trolley during those spans of the trolley system where the shackle is being elevated or turned. Also, this type of system still requires the guide rails at the processing stations.
U.S. Pat. No. 6,179,702 includes a more firm and reliable locking system for temporarily locking a shackle in a fixed position with respect to its processing line. A cam follower and its lock pin are carried by the hanger support, and the cam lock and its lock pin are movable so as to move the lock pin into and out of lock notches of the turning block. When the shackle moves between guide rails, the cam lock is engaged, thereby moving the lock pin out of a lock notch of the turning block and unlocking the turning block and its shackle and allowing them to rotate with respect to the processing line. When the shackle moves beyond its turning area, the force applied to the cam lock is released and a spring urges the lock pin back into engagement with the turning block, thereby locking the shackle in its new position.
One of the problems with the preceding described positioning lock is that a precise relationship must be maintained between the cam and the cam follower so as to reliably lock and release the shackle, and repeated use and wear applied to the cam and the lock notches results in unreliable locking of the shackle and requires that the cam lock occasionally be replaced for continued reliable operation. It is to the above noted and other problems of the prior art that this invention is directed.
Briefly described, the present invention comprises a rotary shackle for transporting poultry carcasses along a poultry processing line that reorients the shackles as the birds carried by the shackles are approaching a processing station, such as a cut-up station. The shackle assembly includes a turning block that engages turning pins at the entry of the various processing stations. The turning block is approximately square and includes turning slots at its comers that engage and xe2x80x9cwalk aroundxe2x80x9d turning pins that are positioned along the path of the turning block. Upon engaging a turning pin, the turning block will rotate 90xc2x0. The turning block can be rotated 180xc2x0 upon engagement of two consecutive turning pins. The turning block can be rotated in either direction by engaging turning pins on opposite sides of its processing path.
The shackle has a vertically oriented support rod with a first or upper end for suspension from a suspended conveyor line and a second or lower end for suspension below the upper end, with stirrups mounted on the lower end. The stirrups are configured for supporting the legs of a poultry carcass. The turning block is non-rotatably mounted to the support rod, so that when the turning block is rotated, the stirrups rotate in unison with the turning block.
A lock gear having lock gear teeth is non-rotatably mounted to the support rod, and the lock collar having lock collar teeth is rotatably mounted to the support rod. The lock collar is movable along the length of the support rod toward and away from engagement with the lock gear. The lock gear teeth and lock collar teeth are of complementary shape that lock together in response to the teeth coming together about the support rod.
When the shackle is to be rotated by its turning block, the lock collar and lock gear separate from each other, freeing up the shackle so that it can freely rotate. The turning gear then engages a turning pin and rotates the shackle to its desired position, whereupon the lock collar and lock gear re-engage each other, locking the shackle and the bird carried by the shackle in the proper position for presentation of the bird to the next processing station, such as to a cut-up station.
In the embodiment disclosed herein, the lock collar defines an interior space, with the lock collar teeth projecting into one portion of the cavity. Another portion of the cavity accommodates the lock gear teeth when the lock gear teeth are not in locking engagement with the lock collar teeth. When the lock collar moves longitudinally with respect to the shackle, the lock gear teeth move in the cavity until they engage and lock with respect to the lock gear teeth. With this arrangement, the lock gear teeth are always maintained inside the lock collar, so that the hazard of items becoming jammed between the teeth and of the teeth accumulating debris or other undesirable matter is substantially reduced. The lock collar forms a protective cover for its teeth and for the lock gear teeth.